含LiAlO2-Y2O3复合助烧剂的氮化硅陶瓷低温致密化研究  

Low temperature densification of silicon nitride ceramics with LiAlO2-Y2O3 as composite sintering additive

作　　者：郭昂 王战民[1] 赵世贤[1] 李凌锋 Guo Ang;Wang Zhanmin;Zhao Shixian;Li Lingfeng(State Key Laboretore of Advanced Refrectories,iinosteel Luoyang Institute of RetoctoSgs Research Co.,Lti.,Luoyang 471039,Henan,China)

机构地区：[1]中钢集团洛阳耐火材料研究院有限公司先进耐火材料国家重点实验室,河南洛阳471039

出　　处：《耐火材料》2020年第5期369-373,共5页Refractories

基　　金：国家重点研发计划资助项目(2017YFB0310300)。

摘　　要：以高α相含量的Si3N4粉体为主要原料,LiAlO 2-Y2O3作为复合助烧剂,在无压条件下烧结Si3N4陶瓷,研究了LiAlO2-Y2O3助烧剂体系对Si3N4陶瓷烧结致密化过程、相变过程和显微结构的影响。结果表明:LiAlO2-Y2O3助烧剂对Si3N4陶瓷致密化温度的降低和相转变速率的提高有明显作用,在1500℃有低共熔点液相LiAlSi 3O 8生成,且α-Si3N4向β-Si3N4的相转变开始进行,埋碳烧结时被氧化部分为试样表面。在LiAlO2-Y2O3助烧剂体系中,对Si3N4陶瓷低温致密化起主导作用的是LiAlO 2,当LiAlO 2加入量为8%(w)时试样的相对密度达到98.1%,且可以得到发育良好的柱状β-Si3N4晶粒。而Y2O3对α-Si3N4向β-Si3N4的相转变速率有明显提高,随着Y2O3加入量的增加,β-Si3N4转化率随之提高。当Y2O3加入量为8%(w)时β-Si3N4转化率达到91%。Si3N4 ceramics were prepared by pressureless sintering using highα-phase content Si3N4 powder as the main raw material and LiAlO2-Y2O3 as the composite sintering additive.The effect of LiAlO2-Y2O3 sintering additive on the sintering densification,the phase transformation and the microstructure of Si3N4 ceramics was researched.The results show that the addition of LiAlO2-Y2O3 can play a significant role in reducing the sintering densification temperature and promoting the phase transformation rate of the Si3N4 ceramics;at 1 500℃,a low melting point phase LiAlSi3O8 is formed andα-Si3N4 begins to transform toβ-Si3N4;the oxidized part of the specimen during cabon embedded sintering is the surface.In the system of LiAlO2-Y2O3 sintering additive,LiAlO2 plays as a leading role in the low-temperature densification of Si3N4 ceramics.When the LiAlO2addition is 8 mass%,the relative density of the specimen reaches 98.1%,and the well developed elongated β-Si3N4 grains can be obtained.Y2O3 can promote the phase transformation rate of α-Si3N4 to β-Si3N4,which increases with the rising Y2O3 addition.When the Y2O3 addition is 8 mass%,the conversion rate of β-Si3N4 is 91%.

关 键 词：氮化硅 LiAlO2-Y2O3助烧剂 致密化 β-Si3N4转化率 

分 类 号：TQ175[化学工程—硅酸盐工业]